It is extemely common for commercial buildings and dwellings to have closures, such as doors, that may be opened only by key or combination lock from the outside. The security of the tenants demands appropriate selective entrance.
Such locking systems attempt to find a balance between simplicity of operation with maximum security. As in all such devices the achieving of the one is at the sacrifice of the other. The simpler the locking system for operation the simpler the locking system may be defeated. In contrast, the more complicated the locking system the more secure the locking system; but also, the more cumbersome the operation.
In those instances where maximum security is demanded, the complicated locking systems can prove to be a severe aggravation to those that use the closure. If the locking system is a key operation, the necessity of carrying an extra key can be an aggravation. If the locking system is a combination lock the setting of the lock on the precise numbers is similarly cumbersome. In many instances it is the elderly that require the maximum security; but yet, the elderly are the least capable of manipulating a complicated locking system.
It is appreciated therefore, that there is a need for such a locking system that is extemely secure; but yet, not so cumbersome that all cannot readily operate the locking system with a minimum of inconvenience.